Just so you know, the bad allocation error is essentially an out of memory issue. This can definitely be an issue with extremely large and complex models if the OS doesn't have enough spare memory. If you think about it, you have to render the complex mesh on screen, then render a very intensive preview simulation, and also load most of the gcode file into memory for uploading to the machine. Creator does a great job at doing all this multitasking as fast as possible, but that's still a lot of memory! We have made a consistent effort to minimize this as much as possible, but it can definitely pop up depending on the size of files you are working with and what hardware you're running on.

I looked at the STL you are working with and it creates a pretty large gcode file when sliced. It's made up of almost completely circles so it takes thousands of tiny lines to model it. For files of this size I would definitely suggest printing the gcode directly from the SD card. We're still working on making our USB communication a little more robust, so printing from the SD card will avoid any chance of the build stopping midway like it did here.

We'll get it fixed, but the SD card is definitely safer for now (and gives better quality anyways since there's less overhead!)

Well the best way to do that is to simply print directly from the SD card That is always a more reliable approach and doesn't rely on your CPU for all the constant communication back and forth.

We did make a few changes in version 1.0.6 that will help with this problem some. We will continue to look for ways to improve the memory footprint, but when you're dealing with massively complex models and huge gcode files, it's going to be hard to avoid. For your original question, if you stop the preview and delete the imported model, that should remove the memory associated with those tasks. But again, I suggest printing the file from the SD card if you're having issues with these big models.